The present invention relates to a network relay apparatus, such as switch or router.
The network relay apparatus has an important role of relaying data in a computer network. There has been significant performance improvement and capacity increase of the network relay apparatus, accompanied with scale expansion of the computer network and an increase in amount of data transmitted in the computer network. Such performance improvement and capacity increase of the network relay apparatus, however, tends to increase power consumption of the network relay apparatus. It is accordingly required to reduce power consumption of the network relay apparatus, i.e., to achieve power-saving of the network relay apparatus.
One proposed measure enables generation of a high clock signal having relatively high frequency and a low clock signal having relatively low frequency and switches over the clock signal used to drive a processing circuit from the high clock signal to the low clock signal, so as to achieve power-saving of the network relay apparatus (see, for example, JP 2007-228490A and JP 2007-228491A). Another proposed technique disclosed in JP 2007-316805, so-called gating, cuts off supply of a clock signal to a memory at regular intervals, so as to achieve power-saving of the network relay apparatus.